There is a continuing interest in printed circuitry miniaturization. In most printed circuit boards in use, circuitry traces are printed by conventional methods, particularly photoresist techniques. Accessory components such as capacitors and resistors are frequently provided as discrete components and soldered onto the printed circuitry, either manually or robotically. These components occupy "real estate" on the printed circuit board and may be difficult or expensive to apply to the board.
Accordingly, structures have been proposed in which components such as capacitors and/or resistors are provided along with circuitry traces by circuitization procedures. Examples of such structures are found in U.S. Pat. Nos. 5,079,069, 5,155,655, 5,161,086, 5,261,153, 5,347,258, and 5,466,892, the teachings of each of which are incorporated herein by reference. Typically, a plurality of such structures are laminated together with dielectric material to form multi-layer printed circuit boards.
Embedded circuitry components including conductive traces, resistors, capacitors, and inductors, and components containing all of the above may be produced by chemically processing thin films. The term "thin film material" is meant herein to encompass single layer films, such as metal foils, as well as thin film laminates such as a laminate of two or more layers having specific electrical properties or a laminate of a support film and one or more layers of material having specific electrical properties.
Because such thin film materials have very little mechanical stability and would not by themselves survive conveyorized chemical processing, they must be supported on a rigid carrier. The thin film material may be held to the carrier by a rigid frame or by tape along its edges. Mechanical frames are labor-intensive to apply and remove. Tape has been known to come off during processing, resulting in damage to the thin film material being processed.